Some injection molded articles, for example plastic preforms of the variety that are for blow molding into beverage bottles, require extended cooling periods to solidify into substantially defect-free molded articles. To the extent that the cooling of the molded article can be effected outside of the injection mold by one or more post-mold device then the productivity of the injection mold may be increased (i.e. lower cycle time). A variety of such post-mold mold devices, and related methods, are known and have proven effective at the optimization of the injection molding machine cycle time.
In a typical injection molding system a just-molded, and hence only partially cooled, molded article is ejected from the injection mold and into a post-mold device, commonly known as a take-out device or end-of-arm-tool (EOAT), having a cooled carrier (otherwise known as a cooling tube, take-out tube, cooling sleeve, amongst others) for post-mold cooling of the molded article outside of the mold.
U.S. Pat. No. Re. 33,237 describes a post-mold device for removing partially cooled injection molded preforms from the core side of an injection mold. The preforms are ejected from the mold directly into cooled carriers (such as that described in commonly assigned U.S. Pat. No. 4,729,732), and transported by the post-mold device to an outboard position adjacent the mold. The post-mold device includes multiple sets of carriers to accommodate multiple sets of preforms (i.e. multiple shots of preforms).
Commonly assigned U.S. Pat. No. 6,171,541 describes another post-mold device that includes a set of cooling pins for insertion into the interior of a partially cooled preform, the preform arranged in a cooled carrier of the first post-mold device, to discharge a cooling fluid therein. An example of the foregoing is sold under the trade name of COOLJET, a trade-mark of Husky Injection Molding Systems Limited. Also disclosed is a procedure to apply a vacuum through the same cooling pin to cause the preform to remain with the pin when it is moved away from the carrier holding the preform, thereby removing the preform from the carrier. The pins, mounted to a frame, may be rotated 90 degrees to a discharge position and the vacuum terminated to allow the preforms to fall off the pins.
While the preforms are held by the pin, under vacuum, there may be contact between the end of the pin and the inside surface of the preform, or, between the open end of the preform and a face of a plate upon which the pins are arranged. As the preform is typically blown into an aseptic bottle, it is not accepted by all to touch the inside or end surfaces of the preform with the tooling (i.e. pin or plate) for fear of contamination.
U.S. Pat. No. 5,114,327 describes an post-mold device for cooling a molded article. The post-mold device includes a receiver and cooling head that cooperate for circulating, and subsequently recovering, a coolant, such as liquid carbonic, around the molded article.
U.S. Pat. No. 6,802,705 describes a post-mold device for cooling an end portion of the molded article. The post-mold device includes a deflecting plate insert for directing a coolant flow over an exposed end portion of a molded article, such as a preform, that is arranged in a carrier of a post-mold device.